Ecological Monitoring

Abstract

Ecological monitoring aims at inferring causes of ecosystem changes, by measuring ecosystem state variables in space and time.
This is required for management, when different actions are possible and their consequences need to be assessed and compared,
and for science, which aims at establishing the causes of observed patterns. The success of an ecological monitoring programme
will heavily depend on having well‐articulated questions and objectives, formulated using a simple conceptual model. Future
challenges lie in integrating monitoring programmes through questions and models that include both global and local scales,
and adding the human dimension in order to achieve social‐ecological monitoring.

Key Concepts:

Many ecological monitoring programmes have been inefficient and passive.

Ecological monitoring should start with simple model(s) and questions.

The model(s) and questions should be frequently confronted with data, and changed if necessary.

Developments in statistics and other fields are crucial for accurate estimation of state variables.

Long‐term ecological research (LTER) sites are examples of successful monitoring, with major results.

More work is needed to integrate monitoring programmes in order to achieve local and global objectives.

Social and economic aspects, such as ecosystem services, need to be added to monitoring programmes.

Riparian habitats in Arctic tundra can be found along a continuum of states, from a state dominated by large willow shrub
patches (a) to a state without such shrub cover (b). These states have different structure – species dependent on willow shrubs
such as willow grouse disappear in state (b) – as well as different functions – for example, increasing shrub cover will decrease
albedo ((c) contrast the dark shrubs and the white snow cover) and therefore will affect climate. Climate change represents
an important driver of a transition from (b) to (a) – warmer temperatures favour shrub growth – but herbivores, and in particular
reindeer, may slow down or even reverse shrub cover increase ((a)–(b)). Furthermore, climate change may negatively influence
small mammalian herbivores, such as lemmings ((d) dead Norwegian lemming on hard snow), with consequences for emblematic,
predatory species (Snowy owl; (c)). Ecological Monitoring starts with a simple model of the interactions between climate,
shrub cover, herbivores and their predators, and incorporates the human dimension, particularly reindeer herding and indigenous
people. Because Arctic terrestrial ecosystems cover huge areas, with large variation in present state, history (e.g. presence
of ice during the last Glacial Maximum), diversity, climate regime, socio‐economic condition and governance, monitoring needs
to integrate local (‘context’) and global components. Reproduced from Nigel Yoccoz (a) and Rolf A Ims ((b)–(d)).